Muffler



'Patented oa. 22, 1929 PATENT fol-FICE Y VIRGIL OLDBERG, F HIGHLANDPARK, MICHIGAN MUFFLEB Applicationled November 14, 1927. Serial No.233,046.

This invention relates to means for reducing the sound of the exhaust ofinternal combustion engines, and its object is to provide a device ofthis character which shallrbe simple in construction and ofcomparatively low cost of production.

I have been marketing mulilers bullt up of two ends or heads and threecylindrical shells connecting them, the intermediate' s hell beingeccentric to the others, the ends being provided with intake and outletopenings and the shells being perforated to cause the exhaust gases totravel tortuous courses to cause the independent charges of exhaustgases en- I tering the muilers to merge so that the gases will leave ina substantially uniform stream.

This muiller is shown by my Patent Number 1,542,829 dated June 23, 1925.The present muffler embodies the saine heads but has only twoshells anda short plate secured to the inner shell. Y

In the accompanying drawing Fig. 1 is a central longitudinal sectionowfv my novel muffler;

Figs. 2 and 3 are sections on the lines 2 2 and 3 3 of Figure lrespectively.

The heads or ends 1 and 2 are preferably similar in construction,differing only in that the head 1 has a central flange 3 to receive theintake pipe which is larger in diameter than the discharge pipe 5 whichresults in the flange 6 on the head 2 being smaller in diameter than theflange 3. These heads are preferably sheet metal stampings, each beingormedwith a cylindrical outer flange 8 toreceive the outer shell 9 andwith an intermediate cylindrical portion 10 to receive the inner shell11. All parts of this mufller are preferably united by welding.

The inner shell is formed with groups of holes 13 and 14, one at eachside of the parti-- tion 15 which divides it into two chambers,thegroups being preferably diametrically oppositeeach other. A plate 16bent to constitute a section of a cylinder has its longitudinal endsbent inwardly to constitute flanges 17 which are secured to the innershell so that holes 13 will impinge 'against this plate andu `parts ofthis mu pass circumferentially partially around the inner shell and thenescape into the 4main space between thetwo shells.

The greatest value of the formerly used intermediate shell was thatthesound of the exhaust passing out through holes in the inner shell andimpinging on the intermediate shell was mullled by the gases in thespace between the intermediate and outer shells. The sound of the gasesimpinging on this plate 16 is similarly muflled while at the Sametimethe space between the shells 11 and 9 erm'its the exhaust 'impulses tomerge into eac other before the gases pass inwardly through the holes 14into the second chamber of the inner shell from which they escape in asubstantially constant stream through the pipe 5.

While these gases are passing through the muiller they cool and theirvolume and pressure are both reduced. The present-muliler approximatesthe earlier mufller in efliciency and can be more cheaply produced.

.The details and iiproportions of the different er may all be changed bythose skilled in the art without departing from the spirit of myinvention asset forth in the following claims.

'I claim A 1. A muiiler comprising ends and pipes connected thereto, twoshells connecting said ends, one shell being within the other, apartition within the inner shell dividing it into inlet and outletchambers, said inner shell being formed with groups of holes 0n eachside of the partition, a plate secured to the inner shell and extendingover one of the groups of holes therein, and pipes connecting into saidends.

2. A muffler comprising two heads and pipes connecting into them, twoconcentric cylindrical shells connecting said heads, a

partition within the inner shell, said inner 'of said inner shellover'one group of holes and spaced therefrom suiciently to permit gasesto pass circumferentially between the plate alllnl shell into' the spacebetween the two s el s.

3. A muffler comprising two heads and pipes connecting into them, twoconcentric cylindrical shells connecting said heads,-a partition withinthe inner shell, said inner shell being formed with a group of holes ateach side of said partition, and a cylindrical plate secured at its endsto the outer surface of said inner lshell over one group of holes andspaced therefrom suiiiciently to permit gases to pass circumferentiallbetween the plate and shell into the space getween the two shells, thetwo groups of holes being positioned diametrically opposite each other.

VIRGIL kOLDBERG.

